In this article Barry Mavin, CEO and Chief Software Architect for Recital, details how to use the Client Drivers provided with the Recital Database Server to work with local or remote server-side OLE DB data sources.
Overview
The Recital Universal .NET Data Provider provides connectivity to the Recital Database Server running on any supported platform (Windows, Linux, Unix, OpenVMS) using the RecitalConnection object.
The Recital Universal JDBC Driver provides the same functionality for java applications.
The Recital Universal ODBC Driver provides the same functionality for applications that use ODBC.
Each of the above Client Drivers use a connection string to describe connections parameters.
The basic format of a connection string consists of a series of keyword/value pairs separated by semicolons. The equal sign (=) connects each keyword and its value.
The following table lists the valid names for keyword/values.
| Name | Default | Description |
|---|---|---|
|
Data Source
|
The name or network address of the instance of the Recital Database Server which to connect to. | |
| Directory | The target directory on the remote server where data to be accessed resides. This is ignored when a Database is specified. | |
|
Encrypt |
false | When true, DES3 encryption is used for all data sent between the client and server. |
| Initial Catalog -or- Database |
The name of the database on the remote server. | |
| Password -or- Pwd |
The password used to authenticate access to the remote server. | |
| User ID | The user name used to authenticate access to the remote server. | |
|
Connection Pooling |
false | Enable connection pooling to the server. This provides for one connection to be shared. |
| Logging | false | Provides for the ability to log all server requests for debugging purposes |
| Rowid | true | When Rowid is true (the default) a column will be post-fixed to each SELECT query that is a unique row identifier. This is used to provide optimised UPDATE and DELETE operations. If you use the RecitalSqlGrid, RecitalSqlForm, or RecitalSqlGridForm components then this column is not visible but is used to handle updates to the underlying data source. |
| Logfile | The name of the logfile for logging | |
| Gateway |
Opens an SQL gateway(Connection) to a foreign SQL data source on the remote server. Using Gateways, you can transparently access the following local or remote data sources:
The gateway can be specified in several formats: servertype@nodename:username/password-database e.g. oracle@nodename:username/password-database mysql@nodename:username/password-database postgresql@nodename:username/password-database -or- odbc:odbc_data_source_name_on_server oledb:oledb_connection_string_on_server jdbc:jdbc_driver_path_on_server;jdbc:Recital:args |
To connect to a server-side OLE DB data source, you use the gateway=value key/value pair in the following way.
gateway=oledb:oledb_connection_string_on_server
ImportantWhen specifying the connection string be sure to quote the gateway= with "...".
You can find examples of connection strings for most ODBC and OLE DB data sources by clicking here.
Example in C# using the Recital Universal .NET Data Provider:
////////////////////////////////////////////////////////////////////////
// include the references below
using System.Data;
using Recital.Data;
////////////////////////////////////////////////////////////////////////
// The following code example creates an instance of a DataAdapter that
// uses a Connection to the Recital Database Server, and a gateway to
// the SQL server Northwind database. It then populates a DataTable
// in a DataSet with the list of customers. The SQL statement and
// Connection arguments passed to the DataAdapter constructor are used
// to create the SelectCommand property of the DataAdapter.
public DataSet SelectCustomers()
{
string gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
Data Source=localhost;Integrated Security=SSPI";
RecitalConnection swindConn = new
RecitalConnection("Data Source=localhost;gateway=\""+gateway+"\");
RecitalCommand selectCMD = new
RecitalCommand("SELECT CustomerID, CompanyName FROM Customers", swindConn);
selectCMD.CommandTimeout = 30;
RecitalDataAdapter custDA = new RecitalDataAdapter();
custDA.SelectCommand = selectCMD;
swindConn.Open();
DataSet custDS = new DataSet();
custDA.Fill(custDS, "Customers");
swindConn.Close();
return custDS;
}
Example in Java using the Recital Universal JDBC Driver:
////////////////////////////////////////////////////////////////////////
// standard imports required by the JDBC driver
import java.sql.*;
import java.io.*;
import java.net.URL;
import java.math.BigDecimal;
import Recital.sql.*;
////////////////////////////////////////////////////////////////////////
// The following code example creates a Connection to the Recital
// Database Server, and a gateway to the SQL server Northwind database.
// It then retrieves all the customers.
public void SelectCustomers()
{
// setup the Connection URL for JDBC
String gateway = "oledb:Provider=sqloledb;Initial Catalog=Northwind;
Data Source=localhost;Integrated Security=SSPI";
String url = "jdbc:Recital:Data Source=localhost;gateway=\""+gateway+"\";
// load the Recital Universal JDBC Driver
new RecitalDriver();
// create the connection
Connection con = DriverManager.getConnection(url);
// create the statement
Statement stmt = con.createStatement();
// perform the SQL query
ResultSet rs = stmt.executeQuery("SELECT CustomerID, CompanyName FROM Customers");
// fetch the data
while (rs.next())
{
String CompanyID = rs.getString("CustomerID");
String CompanyName = rs.getString("CompanyName");
// do something with the data...
}
// Release the statement
stmt.close();
// Disconnect from the server
con.close();
} Many motherboards nowadays have integrated gigabit ethernet that use the Realtek NIC chipset.
The Realtek r8168B network card does not work out of the box in Redhat/Centos 5.3: instead of loading the r8168 driver, modprobe loads the r8169 driver, which is broken as can be seen with ifconfig which shows large amounts of dropped packets. A solution is to download the r8168 driver from the Realtek website and install it using the following steps:
Check whether the built-in driver, r8169.ko (or r8169.o for kernel 2.4.x), is installed.
# lsmod | grep r8169
If it is installed remove it.
# rmmod r8169
Download the R8168B linux driver from here into /root.
Unpack the tarball :
# cd /root
# tar vjxf r8168-8.012.00.tar.bz2
Change to the directory:
# cd r8168-8.012.00
If you are running the target kernel, then you should be able to do :
# make clean modules
# make install
# depmod -a
# insmod ./src/r8168.ko (or r8168.o in linux kernel 2.4.x)
make sure modprobe knows not to use r8169, and that depmod doesn’t find the r8169 module.
# echo "blacklist r8169" >> /etc/modprobe.d/blacklist
# mv /lib/modules/`uname -r`/kernel/drivers/net/r8169.ko \ /lib/modules/`uname -r`/kernel/drivers/net/r8169.ko.bak
You can check whether the driver is loaded by using the following commands.
# lsmod | grep r8168
# ifconfig -a
If there is a device name, ethX, shown on the monitor, the linux driver is loaded. Then, you can use the following command to activate it.
# ifconfig ethX up
After this you should not see any more dropped packets reported.
So, to create and configure Recital ODBC datasources, you need to use the Window 32 bit ODBC Data Source Administrator or Recital's own Recital Universal ODBC Manager (32-bit).
The Window 32 bit ODBC Data Source Administrator is %windir%\SysWOW64\odbcad32.exe.
The Recital Universal ODBC Manager (32-bit) can be accessed from the Control Panel (icon view).
# recital < mrprog.prgIndividual commands can be executed in shell scripts.
# recital < myprog.prg > myoutput.txt
# recital > myoutput.txt <<END
use customers
list structure
END
# echo "select * from sales!customers where overdue" | recital | wc -l
# recital -c "create database sales"Expressions can be evaluated and used in shell scripts.
# recital -c "create table sales!invoices (id int, name char(25), due date)"
# VER=`recital -e "version(1)"`You can view what command line options are available by typing:
# recital --help
Key features of the Recital scripting language include:
What are the key feature of the Recital database?
- High performance database application scripting language
- Modern object-oriented language features
- Easy to learn, easy to use
- Fast, just-in-time compiled
- Develop desktop or web applications
- Cross-platform support
- Extensive built-in functions
- Superb built-in SQL command integration
- Navigational data access for the most demanding applications
sernet.de maintain the latest Samba releases in a yum repository, allowing for an easy and painless install or upgrade of Samba on your yum based Linux distribution.
To install the latest available Samba execute the following commands at the shell:
# cd /etc/yum.repos.d # wget http://ftp.sernet.de/pub/samba/experimental/centos/5/sernet-samba.repo # yum install samba
To upgrade an existing Samba install:
# cd /etc/yum.repos.d # wget http://ftp.sernet.de/pub/samba/experimental/centos/5/sernet-samba.repo ## Note: edit sernet-samba.repo and add the line "gpgcheck=false" otherwise ## it will not install as it is not signed
# yum update samba
Note: These steps will install the very latest build available at sernet.de.
If you require a less bleeding edge version of Samba, use the "tested" repo. This can be found at the following URL: http://ftp.sernet.de/pub/samba/tested/rhel/5
Occasionally as a Linux administrator you will be in the situation where working on a remote server and you are left with no option but to force a reboot the system. This may be for a number of reasons, but where I have found it most frequent is when working on Linux clusters in a remote location.
When the "reboot" or "shutdown" commands are executed daemons are gracefully stopped and storage volumes unmounted.
This is usually accomplished via scripts in the /etc/init.d directory which will wait for each daemon to shut down gracefully before proceeding on to the next one. This is where a situation can develop where your Linux server fails to shutdown cleanly leaving you unable to administer the system until it is inspected locally. This is obviously not ideal so the answer is to force a reboot on the system where you can guarantee that the system will power cycle and come back up. The method will not unmount file systems nor sync delayed disk writes, so use this at your own discretion.
To force the kernel to reboot the system we will be making use of the magic SysRq key.
The magic_SysRq_key provides a means to send low level instructions directly to the kernel via the /proc virtual file system.
To enable the use of the magic SysRq option type the following at the command prompt:
echo 1 > /proc/sys/kernel/sysrq
Then to reboot the machine simply enter the following:
echo b > /proc/sysrq-trigger
Voilà! Your system will instantly reboot.
{linkr:related;keywords:linux;limit:5;title:Related Articles}
{linkr:bookmarks;size:small;text:nn;separator:%20;badges:2,1,18,13,19,15,17,12}
In this article Barry Mavin, CEO and Chief Software Architect for Recital provides details on how the Recital Database Server can be used to provide a solution for Universal Data Integration.
Overview
The Recital Database Server handles universal cross-platform data access to a wide range of data sources. The database server natively handles full remote SQL data access to Recital, Visual FoxPro, FoxPro, FoxBASE, Clipper and older dBase data. Using Bridges, it handles full remote SQL data access to C-ISAM and OpenVMS RMS. Using gateway connections, it handles full remote SQL data access to Oracle, MySQL, PostgreSQL, SQL Server, server-side ODBC, server-side JDBC and server-side OLE DB data sources. With its ability to access data using server-side ODBC, JDBC and OLE DB drivers from clients on all supported operating systems (Windows, Linux, Unix, OpenVMS), the Recital Database Server is an ideal Data Integration Solution for applications of all sizes and complexity.
Universal Data Integration Solutions
There are several ways in which data may be accessed by the Database Server.
Table 1:
Client Universal Data Access solutions for accessing local or remote data.
| Client | Solution |
|---|---|
| Recital | Use remote gateway connections |
| Visual FoxPro | Use the Universal ODBC Driver |
| Java (all platforms) | Use the Universal JDBC Driver |
| .NET Framework | Use the Universal .NET Data Provider |
| Microsoft Office | Use the Universal ODBC Driver |
| Windows Mobile | Use the Universal Compact Framework .NET Data Provider |
| PHP on Linux | Use the Universal ODBC Driver for Linux |
| Mono on Linux | Use the Universal .NET Data Provider |
| Others | If the data source you want to access is not in the list above, then you can use a remote ODBC, JDBC or OLE DB gateway. You can find examples of connection strings for most ODBC and OLE DB data sources by clicking here. |
Table 2:
Windows Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:
| Data Source | Solution |
|---|---|
| Recital | Native support (See table 1) |
| Visual FoxPro | Native support (See table 1) |
| FoxPro | Native support (See table 1) |
| FoxBASE | Native support (See table 1) |
| Clipper | Native support (See table 1) |
| dBase | Native support (See table 1) |
| C-ISAM | Use a bridge (See table 1) |
| Access | Use a gateway connection gateway="oledb:Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\somepath\mydb.mdb;User Id=admin;Password=;" |
| Exchange | Use a gateway connection gateway="oledb:Provider=ExOLEDB.DataSource;Data Source=http://servername/publicstore" |
| Excel | Use a gateway connection gateway="oledb:Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\MyExcel.xls;" |
| Oracle | Use a gateway connection gateway="oledb:Provider=msdaora;Data Source=TheOracleDB;User Id=xxxxx;Password=xxxxx;" |
| SQL Server | Use a gateway connection gateway="oledb:Provider=sqloledb;Data Source=Aron1;Initial Catalog=pubs;User Id=sa;Password=asdasd;" |
| MySQL | Use a gateway connection gateway="oledb:Provider=MySQLProv;Data Source=mydb;User Id=xxxxx;Password=xxxxx;" |
| IBM DB2 | Use a gateway connection gateway="oledb:Provider=DB2OLEDB;Network Transport Library=TCPIP;Network Address=XXX.XXX.XXX.XXX;Initial Catalog=MyCtlg;Package Collection=MyPkgCol;Default Schema=Schema;User ID=MyUser;Password=MyPW" |
| Sybase ASA | Use a gateway connection gateway="oledb:Provider=ASAProv;Data source=myASA" |
| Sybase ASE | Use a gateway connection gateway="oledb:Provider=Sybase.ASEOLEDBProvider;Srvr=myASEserver,5000;Catalog=myDBname;User Id=username;Password=password" |
| IBM Informix | Use a gateway connection gateway="oledb:Provider=Ifxoledbc.2;password=myPw;User ID=myUser;Data Source=dbName@serverName;Persist Security Info=true" |
| Ingres | Use a gateway connection gateway="odbc:dsn=data_source_name" |
| Firebird | Use a gateway connection gateway="odbc:dsn=data_source_name" |
| IBM AS400 iSeries | Use a gateway connection gateway="oledb:PROVIDER=IBMDA400; DATA SOURCE=MY_SYSTEM_NAME;USER ID=myUserName;PASSWORD=myPwd" |
| Interbase | Use a gateway connection gateway="oledb:provider=sibprovider;location=localhost:;data source=c:\databases\gdbs\mygdb.gdb;user id=xxxxx;password=xxxxx" |
| Others |
If the data source you want to access is not in the list above, then you can use server-side ODBC, JDBC or OLE DB. |
Table 3:
Linux and Unix Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:
| Data Source | Solution |
|---|---|
| Recital | Native support (See table 1) |
| Visual FoxPro | Native support (See table 1) |
| FoxPro | Native support (See table 1) |
| FoxBASE | Native support (See table 1) |
| Clipper | Native support (See table 1) |
| dBase | Native support (See table 1) |
| C-ISAM | Use a bridge (See table 1) |
| Oracle | Use a gateway connection gateway="oracle:Connection_String" |
| MySQL | Use a gateway connection gateway="mysql:Connection_String" |
| IBM DB2 | Use a gateway connection gateway="db2:Connection_String" |
| PostgreSQL | Use a gateway connection gateway="postgres:Connection_String" |
| Others |
If the data source you want to access is not in the list above, then you can use a server-side JDBC driver. |
Table 4:
OpenVMS Server Universal Data Access solutions accessible from any remote client running on Windows, Linux, Unix or OpenVMS:
| Data Source | Solution |
|---|---|
| Recital | Native support (See table 1) |
| Visual FoxPro | Native support (See table 1) |
| FoxPro | Native support (See table 1) |
| FoxBASE | Native support (See table 1) |
| Clipper | Native support (See table 1) |
| dBase | Native support (See table 1) |
| RMS | Use a bridge (See table 1) |
| Others |
If the data source you want to access is not in the list above, then you can use a server-side JDBC driver. |
Supported Data Sources
Native Data Access
The Recital Database Server has native built-in support for the following data sources:
- Recital
- Visual FoxPro
- FoxPro
- FoxBASE
- Clipper
- dBase
You can setup tables to work with using the Database Administration Tool in Recital Enterprise Studio.
Bridges
Using Bridges, you can access the following data sources as if they were standard Recital/FoxPro tables:
- CISAM
- OpenVMS RMS
You can setup bridges using the Database Administration Tool in Recital Enterprise Studio.
Gateways/Connections
Using Gateways, you can transparently access the following local or remote data sources:
- Recital
- Oracle
- ODBC (Server-side ODBC data sources)
- JDBC (Server-side JDBC data sources)
- OLEDB Use this to connect to SQL Server and other Windows OLE DB data sources)
- MySQL
- PostgreSQL
Remote Data Object functions
Recital 10 includes a complete and robust set of data source independent functions for accession MySQL, Oracle, DB2 and Postgres. This article explains how to use them.
Client Data Access drivers
Included with the Recital Database Server are three Client drivers. These Client drivers can access any data sources supported by the Recital Database Server. They are not restricted to accessing only Recital data. They can be used to access server-side ODBC, JDBC and OLE DB data sources also.
Recital Universal .NET Data Provider
Use this client driver when building .NET applications with Visual Studio .NET. A data provider in the .NET Framework serves as a bridge between an application and a data source. A data provider is used to retrieve data from a data source and to reconcile changes to that data back to the data source.
Key features of the Recital Universal .NET Data Provider:
- Fully Internet enabled
The Recital Universal .NET Data Provider works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS. - SQL Server compatible
The Recital Universal .NET Data Provider is plug compatible with the .NET Framework SQL Server Data Provider. - Cross-platform Data Integration
Using the Recital Universal .NET Data Provider, you can connect to remote Windows, Linux, Unix or OpenVMS servers and access any data source supported by the Recital Database Server. - Managed code
The Recital Universal .NET Data Adaptor written in C# is 100% .NET Framework managed code. - Runs on Windows Mobile
The Recital Universal .NET Data Adaptor runs under the .NET Compact Framework on Windows Mobile.
Recital Universal JDBC Driver
The JDBC API is the industry standard for database-independent connectivity between the Java programming language and a wide range of databases. The JDBC API provides a call-level API for SQL-based database access. JDBC technology allows you to use the Java programming language to exploit "Write Once, Run Anywhere" capabilities for applications that require access to enterprise data.
Key features of the Recital Universal JDBC Driver:
- Fully Internet enabled
The Recital Universal JDBC driver works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS. - JDBC 3.0 API
The Recital Universal JDBC driver supports the JDBC 3.0 API. - Pure Java Type 3 Driver
The Recital Universal JDBC driver is a 100% pure Java Type 3 driver. - Full Access to Metadata
The JDBC API provides metadata access that enables the development of sophisticated applications that need to understand the underlying facilities and capabilities of a specific database connection. - Cross-platform Data Integration
Using the Recital Universal JDBC driver, you can connect to remote Windows, Linux, Unix or OpenVMS servers and access any data source supported by the Recital Database Server. - No Installation
A pure JDBC technology-based driver does not require special installation; it is automatically downloaded as part of the applet that makes the JDBC calls. The Recital Universal JDBC Driver is 100% java.
Recital Universal ODBC Driver
Connect to remote data from Microsoft Office or other applications that support ODBC data access. The Recital Universal ODBC Driver is also available for Linux and Unix.
Key features of the Recital Universal ODBC Driver:
- Fully Internet enabled
The Recital Universal ODBC driver works across the internet providing access to a wide range of data sources located on remote servers running Windows, Linux, Unix and OpenVMS. - Works with Crystal Reports
The Recital Universal ODBC driver supports the SQL syntax generated by Crystal Reports. - Works with Microsoft Office
The Recital Universal ODBC driver works with Microsoft Office products. - Works with PHP on Linux
The Recital Universal ODBC driver is available for Linux and works with PHP.
$hdiutil create /tmp/tmp.dmg -ov -volname "RecitalInstall" -fs HFS+ -srcfolder "/tmp/macosxdist/"
$hdiutil convert /tmp/tmp.dmg -format UDZO -o RecitalInstall.dmg